Reynolds-number effects in turbulent boundary layers around wing sections

Authors: Vinuesa, R., Singh Negi, P.S.N., Atzori, M.A., Hanifi, A., Henningson, D.S.H., Schlatter, P.
Document Type: Article
Pubstate: Accepted
Journal: 12th ERCOFTAC Symp. on Engineering Turbulence Modeling and Measurements (ETMM12), Montpellier, France, September 26-28
Year: 2018


Four well-resolved LESs of the turbulent boundary layers around a NACA4412 wing section, with Re c ranging from 100, 000 to 1, 000, 000, were performed at 5 • angle of attack. By comparing the turbulence statistics with those in ZPG TBLs at approximately matching Re τ , we find that the effect of the adverse pressure gradient (APG) is more intense at lower Reynolds numbers. This indicates that at low Re the outer region of the TBL becomes more energized through the wall-normal convection associated to the APG. This is also reflected in the fact that the inner-scaled wall-normal velocity is larger on the suction side at lower Reynolds numbers. In particular, the wing cases at Re c = 200, 000 and 400, 000 exhibit wall-normal velocities 40% and 20% larger, respectively , than the case with Re c = 1, 000, 000. Consequently , the outer-region energizing mechanism associated to the APG is complementary to that present in high-Re TBLs.